1. Field of the Invention
This invention relates to preparation and use of a poly(p-phenylene terephthalamide) (PPD-T) combination of materials which includes PPD-T and polyvinyl pyrrolidone (PVP); and to processes for making shaped articles made from that combination. Solutions in which the combination was formed during polymerization of the PPD-T can be used to make the shaped articles.
2. Description of the Prior Art
European Patent Publications No. 381,172, published Sep. 8, 1990 and No. 396,020, published Nov. 7, 1990, disclose what is termed a homogeneously mixed alloy of aromatic polyamides and PVP. It is said that the component parts of the alloys of these publications are completely miscible and exhibit a single glass transition temperature between those of the polyamide and the PVP. It is, also, stated that the PVP can be used in the alloy in concentrations of 2% to 98%, with 30% to 70% preferred; and that the PVP is not leached out of the alloy by water. The aromatic polyamides exemplified in those publications are substantially noncrystalline. PPD-T is not mentioned in those publications; and the publications contain no recognition of any differences between a system wherein aramids are polymerized in the presence of PVP and a system wherein completely polymerized aramids are merely dissolved in the presence of PVP.
European Patent Publication No. 401,740, published Dec. 12, 1990 discloses that completely polymerized PPD-T can be dissolved with completely polymerized PVP to make a fiber spinning dope to spin fibers which exhibit the tensile properties of the PPD-T and the moisture uptake and dyeability properties of the PVP.